CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to the following co-pending application Ser. No. 08/233,835, entitled "Benzocycloalkylazolethione Derivatives", filed contemporaneously herewith and incorporated herein by reference.
1. Field of the Invention
This invention relates to a novel process for preparing 1-benzocycloalkyl-1,3-dihydroimidazole-2-thiones and the pharmaceutically acceptable acid addition salts thereof, which are dopamine .beta.-hydroxylase inhibitors.
2. Description of the Field
Dopamine is a catecholamine neurotransmitter found predominately, along with specific dopaminergic receptors, in the central nervous system. Norepinephrine is a circulating catecholamine, which acts at discrete adrenergic receptors in peripheral systems. Dopamine .beta.-hydroxylase (DBH) catalyzes the conversion of dopamine to norepinephrine and is found in both central and peripheral sympathetic neurons. Inhibition of DBH concurrently elevates dopamine levels by blocking its metabolism and reduces norepinephrine levels by blocking its synthesis. Thus, drugs which inhibit DBH are useful for treating diseases associated with reduced dopamine levels (e.g., Parkinson's disease) and for treating diseases associated with elevated norepinephrine levels (e.g., hypertension, congestive heart failure, etc.). Fusaric acid, a DBH inhibitor, decreases the tremors and other abnormalities associated with Parkinson's disease. Fusaric acid also reduces blood pressure in hypertensive patients; however, release of norepinephrine from the adrenal gland and a resultant tachycardia is also observed. Other more selective DBH inhibitors are known but often possess disadvantageous effects.
Certain 5-aminomethyl-1-benzocycloalkyl-1,3-dihydroimidazole-2-thiones are described as dopamine .beta.-hydroxylase inhibitors in the above-identified co-pending application.